A man who claimed he was protecting himself when he stabbed his pet dog with a kitchen knife has walked free from court.

William Mellis cut an artery at the base of his Staffordshire bull terrier's tail when he used a knife against the animal.

The 31-year-old denied causing unnecessary suffering to the dog, claiming he was trying to protect himself when it became aggressive and bit his hand.

Police were called to his former home after a neighbour reported a disturbance at the Aberdeen flat on Merkland Road on February 18, 2010.

Officers arrived to find the property covered in blood and discovered the animal lying on the kitchen floor in pain and struggling to move.

The dog's owner, who was under the influence of valium and alcohol, was discovered crashed out on the sofa.

Sheriff Graeme Buchanan ruled the case had not been proven following a trial at Aberdeen Sheriff Court on Wednesday.

He said: "I recognise right away that this is an emotive case. But at the end of the day I have to reach a verdict with a cool assessment of the evidence which is available to the court.

"You said that you had been attacked by the dog and there is physical evidence which supports that in that you suffered injuries to your hands which would be consistent with the dog having attacked you.

"In order to obtain a conviction, the Crown would have to prove to the court without a reasonable doubt that the suffering you inflicted on the dog was unneccessary."

Sheriff Buchanan ruled that Mr Mellis, now of Tay Road, Aberdeen, appeared to be in a situation where some action had to be taken to protect himself from the dog.

Grampian Police constable Lisa Wood told the trial she initially thought that Mr Mellis was seriously injured because he was lying on his sofa covered in blood.

She said: "The flat was absolutely covered in blood, on the walls, on the ceiling. The whole of the bathroom was covered in blood.

"There was a male lying in the living room, asleep on the sofa. I thought he had a serious injury when we first entered. I just thought, because he was covered in blood and he was asleep, that he had been knocked out.

"When I got closer, I could see there was no injuries on him. I looked in the door and saw a dog lying on the kitchen floor quite badly injured.

"It was trying to move but it couldn't move, especially not his back end. It was very scared and we could see it was in a lot of pain."

A medical examination later found three bruises on Mr Mellis's head, abrasions on his knuckles and an injury on his thumb.

The dog was taken away by a vet for treatment and has since made a full recovery.

IN DETAIL

• Man accused of stabbing dog was 'covered in blood' when police arrived